| 摘要 |
<p>A transmitter carried by a person in a hazardous situation uses gravity and movement switches to detect a mishap and initiate a distress call. A buzzer on the set sounds immediately if either switch operates, or at regular interval otherwise. A distress call is sent out if the person does not acknowledge the buzzer by pressing a button. The gravity switch has a segment of a metal sphere, free to move like a pendulum, inside an insulating hollow spherical cavity. Two contacts, one projecting into the cavity, the other flush, detect tilt of more than 60 deg. from vertical. The movement switch has a ball free to roll in a spherical cavity and a vibration pick-up on a stud at the bottom of the cavity.</p> |
